1. Field of the Invention
The present invention relates to binaphtol derivatives, represented by the following chemical formula I, suitable for use in the optical resolution of racemic amino acids or racemic amino alcohols or in the optical transformation of amino acids from D-form into L-form or vice versa. Also, the present invention relates to uses of the derivatives in the optical resolution of racemic amino acids or racemic amino alcohols to afford optically pure amino acids or amino alcohols and in the optical transformation of amino acids from D-form into L-form or vice versa.

2. Description of the Related Art
Found in useful applications such as ligands of asymmetric catalysts and building blocks necessary for the synthesis of various physiologically active materials, optically pure amino alcohols are industrially important compounds.
The preparation of optically pure amino alcohol is found in DE Pat. Publication No. 4341605 that discloses a method of synthesizing optically pure amino alcohol from optically pure amino acids. However, because D-form amino acids do not naturally occur, the requirement of the industrial synthesis therefor causes an increase in production cost. Accordingly, the amino alcohols corresponding thereto are also synthesized at an increased cost. Additionally, the method is disadvantageously applied only for the preparation of limited amino alcohols.
Favretto et al., (Tetraheron Lett. 2002, 43, 2581) suggested a method of synthesizing optically pure amino alcohol from chiral epoxide. This method, however, suffers from the disadvantages of having to use expensive chiral epoxide and being poor in yield, regioselectivity, and sterespecificity; thus, this method has a limitation in industrial application.
For that reason, the separation of optically pure amino alcohol from a synthesized racemate may be useful.
In the present invention, an imine bond is first utilized to recognize the chirality of chiral amino alcohols, thereby separating optically pure amino alcohols.
An imine bond, which is a covalent bond that is formed by a reaction of aldehyde with amine, is stronger than non-covalent bonds, but weaker than general covalent bonds, so that it can be reversibly formed. Thus, when chiral amine is recognized through the formation of imine, the strong covalent bond is advantageous to the separation of racemic amino alcohol to each chiral amino alcohols while the reversible formation of the imine bond is very useful in isolating the chiral amino alcohols recognized and separated through the imine bond. However, little study has been done about the separation of chiral amino alcohol through an imine bond.
Meanwhile, study on the use of the compound of the following chemical formula II in recognizing the chirality of amino acids or amino alcohols is disclosed in Org. Lett. Vol. 6, p 2591. The compound readily reacts with amino acids to form imines that exhibit different NMR spectra according to whether the reacted amino acids are in D-form or L-form.

Although the compound of the chemical formula II is useful in differentiating the D-form and L-form of amino acids by NMR, two imines resulting from the reaction of D-form or L-form amino acids therewith are not largely different in stability so that the ratio thereof is no more than 1.2:1. Hence, the compound of the chemical formula II is possible to use as an NMR chiral shift reagent, but impossible to use in separating racemic amino acids or racemic amino alcohols into D- and L-forms. Additionally, the ester linkage between the naphthalene group and the phenyl group in the compound is apt to be readily hydrolyzed.
Amino acids are the basic structural unit of peptides and proteins, which are the major structural components of all body tissues, and the optically pure forms thereof can be used in various purposes. However, because amino acids that naturally occur are only in L-form, D-form amino acids do not meet the demand. Extensive research has been done for methods of preparing pure D-form amino acids at ease and at low cost. Many methods have been developed for preparing optically pure amino acids ((a) Williams, R. M.; Hendrix, J. A. Chem. Rev. 1992, 92, 889. (b) Duthaler, R. O. Tetrahedron 1994, 50, 1539. (c) Maruoka, K.; Ooi, T. Chem. Rev. 2003, 103, 3013.), but nowhere has the optical transformation of amino acids from L-form to D-form been reported, thus far.